Light-blocking plastic bag

ABSTRACT

A plastic bag for produce such as potatoes comprises first and second plastic walls peripherally bonded together. A central plastic wall is positioned between the first and second walls, being peripherally bonded to them. The central plastic wall is opaque to substantially block the passage of light therethrough. Thus, potato greening can be avoided while they are stored in the bag even under bright, fluorescent light.

BACKGROUND OF THE INVENTION

Produce is marketed in plastic bags typically having ventilation apertures, for ease of their distribution to consumers in supermarkets and the like. However, particularly with respect to potatoes, they are subject to “greening” when exposed to light for even a very few days.

As stated in the article of Alexander D. Pavlista entitled Green Potatoes: the Problem and the Solution, in the Neb Guide published by the University of Nebraska, Lincoln, Nebr. (G1437): “Greening (of potatoes) is strongly affected by the cumulative effects of light quality, duration, and intensity. Chlorophyll is green because it reflects green light while absorbing red-yellow and blue light. Chlorophyll formation is most sufficient under red-yellow light. Under green light, practically no potato greening occurs and little occurs under blue or ultra-violet lights. Fluorescent lights induce more greening than incandescent lights.”

“Greening” is undesirable, tending to alter the taste of the potato, and even creating toxic compounds in the potato. Thus, the greening of potatoes represents a significant problem to the industry of produce marketing.

By this present invention, an inexpensive, plastic bag for produce is provided, which is usable in automated processes, and which can protect potatoes or other produce from the harmful light, while at the same time providing a way for the consumer to inspect the produce product within the bag.

DESCRIPTION OF THE INVENTION

In accordance with this invention, a plastic bag for produce is provided which comprises first and second plastic walls, peripherally bonded together. A central plastic wall is positioned between the first and second plastic walls and peripherally bonded to the first and second walls. The central plastic wall is opaque to substantially block the passage of light therethrough, although it may comprise a plurality of layers in which, if desired, one of such layers is light colored, and another dark colored to provide the opaque characteristic.

The plastic bag may initially have an open end to receive produce such as potatoes. The produce may be inserted into the bag in a compartment defined between the second wall and the central, plastic wall, with the first wall being translucent. This translucent first wall may carry printing or the like, identifying the brand and the type of potatoes in a conventional manner. Because of the design of the bag of this invention, it is generally immaterial that the first bag wall is translucent, since the central, generally opaque plastic wall can substantially block the passage of light therethrough, protecting the produce thereon. This may be accomplished by coloring the plastic wall black to provide an opaque characteristic.

Thus, when the produce is placed in the compartment defined between the second wall and the central plastic wall, the central plastic wall protects the potatoes or other produce from light passing through the first plastic sidewall. Then, the produce-filled plastic bags are displayed with the first wall up, so that the brand and description of the potatoes or other produce on the first wall can be displayed. The second plastic wall may also carry printed indicia, but it preferably contains a transparent window, or the second wall may be completely transparent, so that the buyer can inspect the produce in the bag. However, typically, since the bags are stored with the first wall positioned upwardly, little light gets in to irradiate the potatoes or other produce through this transparent portion of the second wall.

The central, plastic wall may comprise a light-colored layer facing the first wall, and an opaque layer, to substantially block the passage of the light, facing the second wall. The purpose of the opaque layer has been described above, i.e. to prevent light passing through the first plastic wall from reaching the produce. However, the opaque wall which may be black or of another dark color in some embodiments, can interfere with the legibility of the printed identification and display of the package on the first wall. Thus, the light-colored layer can serve as a backing, so that the printed material thereon is more visible, and any colors used in the printing on the first wall can be more impressive.

The light-colored layer and the opaque layer of the central plastic wall can comprise a co-extrusion, or they may comprise separate sheets, peripherally joined together, and/or joined together with seal lines across the layers, or by any other bonding technique desired.

The bag can be sealed on all sides except for one end so that, after filling, one added bar type heat seal can fully seal the bag. Alternatively, the bag may be closed with hog ring or the like, if desired.

Thus, an inexpensive bag, capable of automated production and filling, is provided, in which produce such as potatoes can be protected from undesired light irradiation, to avoid greening in the case of potatoes.

Also, a method for storing potatoes is provided, which comprises: inserting the potatoes into a plastic bag, which bag comprises: first and second plastic walls, and a central plastic wall between the first and second walls, the plastic walls being peripherally bonded together. The first plastic wall is typically translucent, and the central plastic wall is opaque, to substantially block the passage of light therethrough. The method further comprises enclosing the potatoes in the plastic bag between the second plastic wall and the central plastic wall, and storing the potatoes with the first plastic wall facing upwardly.

The central plastic wall may define a light-colored layer facing the first wall and a dark-colored layer facing the second wall as described above, to substantially block the passage of the light. Also, in some embodiments, at least a portion of the second plastic wall is transparent, to permit viewing of the produce in the bag.

DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 is a front perspective view, with portions broken away, of a plastic bag for potatoes of this invention.

FIG. 2 is a rear perspective view of the plastic bag of FIG. 1.

FIG. 3 is an exploded perspective view of the plastic bag of FIGS. 1 and 2, showing the separate sheets from which the bag may be made by heat sealing in an automated assembly line.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring to the drawings, FIG. 1 shows plastic bag 10 for produce having first and second plastic walls 12, 14, peripherally bonded together by heat seal 16, as shown on three sides. Initially, fourth side 18 of bag 10 may comprise an open mouth. Potatoes 20 may be inserted into bag 10, and then fourth side 18 may also be sealed, as is conventional.

As shown, bag 10 also carries a central plastic wall 22 which is also peripherally sealed at the mutual seal lines 16 of the respective plastic walls 12, 14, 22, including side 18 after loading of potatoes 20 into bag 10, typically after bag 10 has been sealed on the first three sides 16.

Thus, it can be seen that bag 10 defines a pair of compartments, one of which is the space between walls 12, 22, which is typically empty, and the other of which contains the potatoes 20, namely the space between walls 22 and 14.

First plastic front wall 12 can be seen to carry a printed label, a logo 23, and/or any other desired advertising indicia for identification of the product. Also, first plastic wall 12 may be translucent or even transparent (which is included in the term “translucent”) throughout much of its extent. The surface 24 of central plastic wall 22, which faces wall 12, is of a light color, typically white, so that logo 23, carried on first plastic wall 12, is readily seen against a light colored background, namely the white or other light color surface 24 of central plastic wall 22. This colored surface may be printed or otherwise applied to typically transparent plastic of layer 22.

Turning to FIG. 2, it can be seen that the side 30 of central plastic wall 24 that faces second plastic wall 14 is of a dark, opaque color, for example black printing ink, or an opaque pigment layer, carried on central plastic wall 24, as desired. Thus, central plastic wall 24 is substantially opaque, and does not transmit much light.

Central plastic wall 24 may also comprise co-extruded layers of light and dark plastic, or a pair of separate light and dark plastic sheets, peripherally joined at seal line 16.

In FIG. 2, a view of bag 10 from its other side is shown, with second plastic wall 14 being presented forwardly, and first plastic wall 12 being in the rear. Second plastic wall 14 may also carry writing or other indicia 26, as well as a viewing window 28 through which the potatoes 20 can be seen. If desired, viewing window 28 may be larger, being in area up to the entire extent of second plastic wall 14.

Thus, when the sealed bags 10, containing potatoes, are stored for example in a bin of a supermarket with overhead fluorescent lights irradiating them, they are stored with their first side 12 upwardly, for product identification and to attract consumers. The light that passes through first plastic wall 12 is at least partially reflected by light colored layer 24 of central plastic wall 22, to highlight the logo or other indicia 23 on translucent first side 12. However, light does not penetrate central plastic wall 22 to any significant extent, because of the dark colored, typically black layer 30 on the side of central wall 22 that faces second wall 14. Thus, the potatoes are in substantial darkness, since they are typically stored with transparent window 28 facing downwardly in the produce bin, and fluorescent lights above do not significantly effect them. This creates a significant increase in the useful life of potatoes 20 as a saleable product, preventing their greening.

It can be seen that ventilation holes 32 are provided in the respective first and second plastic walls 12, 14, in a conventional manner.

Thus, a plastic bag is provided in which the lifespan of produce such as potatoes can be significantly lengthened, despite the fact that they are displayed for purchase under fluorescent lights or other brightly lit conditions, which reduces product loss by avoiding the “greening” problem.

The above has been offered for illustrative purchases only, and is not intended to limit the scope of the invention of this application, which is as described in the claims below. 

1. A plastic bag for produce such as potatoes, which comprises: first and second plastic walls, peripherally bonded together, a central, plastic wall between said first and second walls, and peripherally bonded to said first and second walls, said central, plastic wall being opaque to substantially block the passage of light therethrough.
 2. The plastic bag of claim 1 which defines an open end to receive produce such as potatoes.
 3. The plastic bag of claim 1 which carries produce in a compartment defined between said second wall and the central, plastic wall, said first wall being translucent.
 4. The plastic bag of claim 3 in which the central, plastic wall defines a light-colored layer facing the first wall, and a dark-colored layer to substantially block the passage of said light.
 5. The plastic bag of claim 4 in which the light-colored layer and the dark-colored layer comprise a co-extrusion.
 6. The plastic bag of claim 4 in which the light-colored layer and the dark-colored layer comprise separate sheets, peripherally joined together.
 7. The plastic bag of claim 3 which is sealed on all sides.
 8. The plastic bag of claim 7 which comprises ventilation apertures in the first and second sidewalls.
 9. The plastic bag of claim 4 in which at least a portion of the second plastic wall is transparent, to permit viewing of the produce in the bag.
 10. The plastic bag of claim 4 which contains potatoes.
 11. A plastic bag for produce, which comprises: first and second plastic walls, peripherally bonded together, a central, plastic wall between said first and second walls and peripherally bonded to said first and second walls, said central plastic wall being colored to substantially block the passage of light therethrough, said plastic bag defining an open end to receive said produce, the central plastic wall defining a light-colored layer facing the first wall, and a dark-colored layer to substantially block the passage of light, facing the second wall.
 12. The plastic bag of claim 11 in which the light-colored layer and the dark-colored layer comprise a co-extrusion.
 13. The plastic bag of claim 11 in which the light-colored layer and the dark-colored layer comprise separate sheets, peripherally joined together.
 14. The plastic bag of claim 11 which is sealed on all sides.
 15. The plastic bag of claim 11 which comprises ventilation apertures in the first and second sidewalls.
 16. The plastic bag of claim 11 which at least a portion of the second sidewall is transparent, to permit viewing of produce in the bag.
 17. The plastic bag of claim 1 in which said opaque, central plastic wall comprises a dark-colored layer.
 18. The plastic bag of claim 1 in which the opaque, central plastic wall comprises a dark-colored plastic sheet.
 19. The method for storing potatoes which comprises: inserting said potatoes into a plastic bag, which bag comprises: first and second plastic walls, and a central plastic wall between said first and second walls, said plastic walls being peripherally bonded together, said central plastic wall being opaque to substantially block the passage of light therethrough; enclosing said potatoes in said plastic bag between said second plastic wall and the central plastic wall; and storing said potatoes with the first plastic wall facing upwardly.
 20. The method of claim 19 in which said first plastic wall is translucent, and the central plastic wall defines a light-colored layer facing the first wall and a dark-colored layer facing the second wall, to substantially block the passage of said light.
 21. The method of claim 19 in which at least a portion of the second plastic wall is transparent, to permit viewing of the produce in said bag. 